Recent years have seen the significant technical development in digital video apparatuses, and increasing chances for compression-coding a video (moving picture) signal (a plurality of pictures arranged in time series) and recording the video signal onto recording media such as DVDs and hard disks or distributing the video signal on the Internet. The H.264/AVC (MPEG-4 AVC) is one of the image coding standards, and the High Efficiency Video Coding (HEVC) standard is currently being considered as a next-generation standard.
The HEVC standard described in NPL 1 proposes a sample offset process called SAO. The SAO process is a process for adding an offset value to a sample value (pixel value) in an image (reconstructed image) decoded from a bitstream. Accordingly, the reconstructed image in which the SAO process has been performed enables faithful reproduction of an original image (input image) before coding and reduction in image degradation by the coding.